This invention relates generally to forming discrete groups of documents into convenient bundles or books from at least one, and preferably two, side-by-side streams of documents.
A conventional laser printer or other device capable of printing continuously on a web of paper fed through the printer provides printed indicia in spaced relationship on the web, and in side by side-by-side columns, so as to allow the printed web to be slit, and then cut laterally to form successive printed pages. The present invention relates to collating the pages into books, or groups of pages, from the side-by-side web segments so as to make up printed collated pages representing individual books or jobs.
The slitting and cutting of the printed web can be carried out in a conventional cutter of the type sold by the assignee of the present invention, or by others, such as the Bowe Cutter which is manufactured in Europe and is widely sold through out the United States. Such a cutter slits the continuous paper web and provides side-by-side web segments that are in turn cut laterally by a rotary cutter to provide streams of side-by-side documents to an apparatus of the present invention.
This invention relates to a method and apparatus for grouping documents fed downstream, as from a slitter/cutter, in at least one stream of end-to-end documents, and preferably in side-by-side streams of documents, which documents are accumulated in predetermined numbers on a vertically movable elevator/table. Every other group of documents to be separated is shifted laterally so that successive stacks of documents are provided one on top of the other in offset relationship to one another on the elevator/table. The elevator/table is gradually lowered to accommodate a plurality of such alternately offset first and second document groups. After the elevator has accumulated many such groups, the entire bundle is moved off the elevator/table onto a takeway conveyor. A temporary support surface is provided for the documents fed to the elevator when the elevator is being off loaded, and these documents are then transferred from the temporary support surface onto the elevator once the elevator has been unloaded and returned into position for receiving additional documents.
In further accordance with the present invention, the temporary support surface comprises projecting pins that normally reside below the path of movement of the documents prior to movement into a position over the elevator/table. Thus, these pins are shifted in the downstream direction as required to accumulate documents or document groups while the elevator is being off loaded. The elevator is provided with conveyor belts for moving the pile of accumulated document groups from the elevator onto the takeaway conveyor for further processing. Thus, the documents will be stacked so that each group is offset laterally from an adjacent group in the pile in order to facilitate further handling, as for example arranging each of the individual groups or stacks into a corresponding booklet or job.
In its preferred form the mechanism for accomplishing the lateral offset of the documents prior to the elevator/table comprises a plurality of belt conveyors driven in the downstream direction. A slightly angled, relatively wider belt operates in conjunction with weighted spherical rollers provided in a fixed frame over the path of movement of the documents to impart a lateral shifting force on certain of the documents moving downstream. This lateral shifting of every other group or stack of documents is achieved by providing a gate for the documents that directs each of the documents either along a primary path where the documents travel straight downstream, or along a path such that the documents are influenced by the above-described weighted rollers and associated underlying conveyor for achieving the lateral motion required to shift every other group or stack of documents laterally.
Finally, duplicating the above-described structure will allow side-by-side streams of documents to be shifted laterally and collated, the one shifting conveyor system being a mirror image of the other. It will be apparent that the present invention requires some sort of optically readable mark on the first or last page of each job book or group to signal that the next page is another job, book or group. Such a marking system is described in the co-pending case, Ser. No. 09/525,554 filed Mar. 15, 2000 in a application entitled Page Length Marking System for Continuous Paper Web.
In order to provide alternate paths for the documents fed into the mechanism described above, a diverting section is provided at the upstream end of the apparatus of the present invention in order to direct the documents into one or the other of two laterally displaced paths, the one preferably comprising a straight path through the device whereas the other path provides for the lateral shifting of the documents by the mechanism of the present invention.